Soluble methylol phosphine adducts which contain one or more methylol phosphine radicals (PCH2OH) are prepared by reacting in a suitable solvent tris(hydroxymethyl)phosphine with an amide or amine which contains one or more hydrogens attached to trivalent nitrogen. These soluble adducts are particularly valuable for the preparation of thermosetting flame resistant polymers by reacting them with nitrogenous compounds which contain two or more hydrogen and methylol groups attached to trivalent nitrogen. The adducts are also valuable for the preparation of flame-, glow-, wrinkle-, and shrink-resistant knit and woven textiles by causing the adducts to react with nitrogenous compounds in or on the textile structure by application of heat.